| 摘要 |
<p>An automatic blind or curtain suspension system is described comprising a blind headrail (10) or curtain pole carrying at least one suspension device (28) arranged for movement relative to the headrail (10) or pole towards and away from a stop (48) to open and close the blind or curtain. An electric motor (44a) is coupled to the suspension device (28) and operable to cause it to move relative to the headrail (10) or pole. The system includes compression springs (50) adapted to take up additional drive from the motor (44a) once motion of the suspension device (28) is retarded by the stop (48). An automatic controller (12) is provided which detects a monotonic increase in current to the motor (44a) associated with drive from the motor (44a) being taken up by the springs (50) and interrupts current to the electric motor (44a) when the increase in motor current is detected. The controller (12) may also keep track of the position of the suspension device (28) and store its position when the increase in current is detected. Drive to the electric motor (44a) during subsequent operation of the system may then be regulated in dependence upon the stored value to interrupt current to the motor (44a) before the suspension device (28) hits the stop (48) again.</p> |
